1. Field of the Invention
The invention relates to a pen for applying a colour or correction liquid comprising a sleeve part having an outlet port for the colour liquid, a valve comprising at least one spring means and a guiding element, and a sphere associated with the outlet port and serving as an applicator element. The terms "colour or correction liquid", or "colour liquid", are intended to mean not only pigmented liquids, but also correction liquids without colour pigments.
2. Prior Art
In adhesive dispensers or paste applicating devices it has been known (e.g. DE 10 01 624 B and U.S. Pat. No. 2,984,393, respectively) to bias a rod which serves as a valve member into a closed position, via a spring moulded thereto, in which it closes an outlet port of the dispenser or of the device, respectively. These dispensers or application devices, respectively, are, however, only suited for a relatively broad, unprecise application of the materials contained therein. In contrast, however, particularly with colour or correction liquids, an exact, easy and optionally thin-lined application is desirable.
Another adhesive dispenser has been proposed (EP 331 843 A), in which a sphere serves as applicator element and valve member. This sphere is directly actuated by a spring element, such as a spring disk or a spiral spring. The spring element may, however, retain the sphere not at all, or only poorly, against lateral movements when adhesive is being applied with the sphere being pressed back from the outlet port. Thus, only a comparatively imprecise application of material is possible, which may suffice in case of adhesive dispensers, but which is insufficient for applying a colour or correction liquid. This also applies to a dispensing mechanism arranged at a side of a bottle cap and comprising a directly spring-actuated sphere as disclosed in U.S. Pat. No. 1,378,016.
To attain good movability of a colour applying tip in colour applying writing or correction pens, especially when applying correction liquids, and for an exact application thereof, the tip is provided with a sphere that is rotatably mounted in the sleeve part. For colours that have a low viscosity or which dry up quickly it is also important that an outflow of colour and/or solvent is possible only during the colour applying procedure. According to EP 564 410 A1 (comparable solutions also being disclosed in FR 2 665 649 A, FR 461 361 A, FR 329 628 and DE 43 04 910 A), a solution to this problem consists in the sphere acting as applicator element being pressed from the the interior of the sleeve to the rim of the outlet port by a guiding or transmitting element, in particular a rod-shaped element, which is pressed against the sphere by a spiral or helical spring. To apply colour liquid at a desired site on a paper, a pen with a sphere--which may have a small diameter--is pressed against the site, and optionally is moved over the paper, so that the sphere is pressed slightly away from the outflow port against the spring force, and colour can emerge.
The spring, the rod, the sphere and the sleeve thus form a valve which is closed when the tip of the pen is not pressed so as to prevent an undesired flowing out and/or drying up of the colour liquid. The guiding element formed by the rod holds and guides the sphere in the region between the closing and the opening positions. For the required properties of resilience, spiral or helical springs of metal are used. These springs must be mounted with a respective bearing on the guide rod element and on the pen. For mounting on the pen, a bearing part is inserted into the sleeve, e.g. after introduction of the sphere, guide element and spring. To attain the desired valve properties, the two bearings must, however, be exactly spaced apart, and the spring must have the correct resilience properties.
Known pens have the drawback that various small parts, among which is a spring made of metal, must be assembled exactly. Available spiral springs which are suitable for this application, are short and thus can be retained and inserted only poorly. The guiding element, the sleeve and the bearing part are preferably made of plastics. Inasmuch as separation of a metal spiral spring from the other structural elements of different material for disposal purposes is rather complex, such pens constitute undesired two-component refuse.